1. Field of the Invention
The present invention relates to integrated circuits comprising volatile memory elements and logic circuits associated with the volatile memory elements, especially volatile memory elements comprising logic elements or the like.
2. Discussion of the Related Art
An integrated circuit memory may be formed of an assembly of memory elements, or memory cells, possibly arranged in a matrix. The writing and the reading of data into and from the memory elements are performed by means of dedicated logic circuits. A power supply generally provides the power necessary to the proper operation of the components of the memory elements and of the logic circuits. The memory supply is generally obtained by one or several rails connected to all the memory cells and logic circuits and conveying a supply voltage. A memory is said to be volatile in the case where the data stored in the volatile memory elements risk being lost when the memory supply falls below a minimum threshold. Conversely, a memory is said to be non-volatile when the data stored in the memory are kept even on turning-off of the memory power supply.
In the case of a volatile memory, if the data are desired to be kept even when the integrated circuit is not used, the memory supply must be maintained permanently at a level greater than the minimum data conservation threshold, which corresponds to a so-called inactive operating mode or stand-by mode. This thus results in a consumption of the integrated circuit in inactive mode, called the static consumption.
For certain applications, the integrated circuit consumption is a critical factor. The integrated circuits are for example those equipping a cellular phone supplied by the telephone batteries. Indeed, since the batteries of a cellular phone have a limited capacity, it is desired to reduce to a minimum the integrated circuit consumption, in particular in inactive mode which may correspond to a mode where the phone is completely off or to a mode where the integrated circuit is not requested or to a mode where the volatile memory or the volatile memories are not requested.